What I do to get around this is have up to 3 versions, one is to install the demo and acivate it, then copy the complete install to another directory and upgrade that to the next then copy one more time and update that to the latest.
This way I usually have some fall back but it doesnt work all the time 'cause you may inadvertantly update one of the lessors and if you dont archive your updates, theres no going back.